Tadamichi Meguro

Quantitation of urinary o-xylene metabolites of rats and human beings by high performance liquid chromatography

SummaryA high performance liquid chromatographic method for the determination of urinary o-xylene metabolites of rats, volunteers, and workers was described. In rat urine, the major metabolite, indicated by the glucuronic acid reaction, was separated with thin-layer liquid chromatography and identified as o-toluic acid glucuronide by high performance liquid chromatography. Another rather minor metabolite was demonstrated to be o-methyl hippuric acid. One of the major urinary metabolite in volunteers administered o-xylene orally was demonstrated to be o-methylhippuric acid and another minor metabolite was o-toluic acid glucuronide. In the urine of volunteers exposed to 138 ppm of o-xylene for 3 h in an artificial exposure chamber, o-methylhippuric acid was found to be the major metabolite and a minute amount of o-toluic acid glucuronide was found to be the minor metabolite. In the urine of shipbuilding workers, using a thinner containing toluene and xylenes (o-, m- and p-), hippuric acid and methylhippuric acids (o-, m- and p-) were recognized. Thus, urinary o-methylhippuric acid could be an index of o-xylene exposure of workers.

Mercury uptake in vivo by normal and acatalasemic mice exposed to metallic mercury vapor (203Hg degrees) and injected with metallic mercury or mercuric chloride (203HgCl2).

Levels of mercury in the brain and liver of acatalasemic mice immediately following exposure to metallic mercury vapor or injection of metallic mercury were higher than those found in normal mice. Acatalasemic mice had decreased levels of mercury in the blood and kidneys when the levels were compared with those of normal mice, which indicated that catalase plays a role in oxidizing and taking up mercury. Thus, the brain/blood or liver/blood ratio of mercury concentration in acatalasemic mice was significantly higher than that of normal mice. These results suggest that metallic mercury in the blood easily passed through the blood-brain or blood-liver barrier. The levels of mercury distribution to the kidneys of normal and acatalasemic mice, 1 hr after injection of mercuric chloride solution, were higher than that of normal and acatalasemic mice, respectively, 1 hr after injection of metallic mercury.